Field of the Disclosure
This disclosure relates to a telecommunication system and more particularly to access network architecture of a telecommunication system.
Description of the Related Art
As telecommunication systems move into the next generation of network technology, for example wireless networks evolution to 5G, significant investment must be made in new hardware and software to provide the additional capacity required. The scope of the work is significant. For example, in one carrier's wireless network there are 50,000 to 100,000 access nodes that need to be upgraded to support 5G mobile telecommunication. By contrast a few thousands of core nodes are sufficient to support the above access points. To continue with the wireless scenario, the current understanding is that the future 5G network will be an evolution of the current 4G long term evolution (LTE) technology (but higher capacity) complemented with a tightly integrated mm wave layer for densification and capacity. The densification layer may increase the access node count by a factor of two or more.
Within current telecommunications networks, access and core nodes are built using a large set of hardware and software platforms. A wireless eNB is different from an x digital subscriber line (xDSL) digital subscriber line access multiplexer (DSLAM) or a cable Hybrid Fiber-Coaxial (HFC) headend. Core nodes themselves are built using a multitude of software and hardware platforms. For example, there is dedicated hardware/operating system (HW/OS) for a router, dedicated HW/OS for a mobility management entity (MME), and dedicated HW for a radio network controller (RNC).
FIG. 1A illustrates limitations of the current architecture from a network perspective. In particular, access nodes 151a, 151b, 151c, and 151d have dedicated respective central office hardware support 153a, 153b, 153c, 153d. Some known drawbacks for this architecture include application-specific hardware results in a one-to-one hardware to Network function relation. In addition, the network planning phase determines capacity. If actual demand is less than what was planned, there will be stranded capacity. If actual demand is greater than what was planned, there will be congestion. The one-to-one hardware to software mapping limits or prevents load sharing/load balancing.
FIG. 1B shows a high level block diagram of a legacy radio access network (RAN) Access Node currently deployed in 4G networks such as one of the access nodes 151a, 151b, 151c, or 151d. The Access Node 100 shown in FIG. 1 includes various functional blocks to implement the Access Node functionality. The functional blocks include a network interface block 101 that includes a network processor unit (NPU) to provide the necessary Internet Protocol (IP) transport functionality. A call processing block 103 may use a general purpose processor (GPP) with a proprietary software development kit. The radio section 105 includes functionality to convert IP packets to radio frames for the three sectors α, β, and γ by providing processing for lower layers of the seven layer Open Systems Interconnection (OSI) model. For example, the radio section 105 provides processing for the physical layer (PHY), media access control (MAC), and Radio Link Control (RLC) frame processing.
The radio section 105 is typically a proprietary block, implemented with specialized silicon such as various combinations of proprietary digital signal processors (DSPs), field programmable gate arrays (FPGAs), and/or application specific instruction processors (ASIPs). The various components typically run using a proprietary real time operating system (RT-OS). A switching matrix 107 such as serial rapid I/O (SRIO) provides connectivity at Gigabit rates between the different blocks, delivers the radio frames from the radio processing section 105 to the Common Public Radio Interface (CPRI) block 109, which in turn supplies the radio frames to the radio equipment (not shown) over the CPRI defined interface.
Current Access Nodes have different combinations of hardware, software, and instruction set architectures (ISAs) that differ from vendor to vendor and product generation to product generation. The various Access Nodes typically utilize multiple proprietary development tools for multiple ISAs that can be found in the current Access Node. For example, the ISAs may include the NPU ISA, GPP ISA, and the various ISAs used in the radio processing block 103.
FIG. 1C shows the well-known protocol stack and processing stages for a 4G eNB. The Packet Data Convergence Protocol (PDCP) provides header compression and decompression of IP data flows using Robust Header Compression (RoHC). The PDCP also provides ciphering and deciphering of user plane and control plane data. The Radio Link Control (RLC) provides data transfer management and the Media Access Control (MAC) layer is one of the two sublayers of the Data Link layer (L2) and manages allocation of radio resources for the uplink and downlink. The physical layer (PHY) provides the physical link and transport over the air interface to the User Equipment. RLC, MAC and PHY together are referred to as the “baseband” functions. GPRS Tunneling Protocol (GTP) includes both signaling and data transfer procedures. Encapsulating Security Payload (ESP) provides for secure IP communications. The UDP/IP stack provides the User Datagram Protocol (UDP) as the transport layer protocol defined for use with the IP network layer protocol. The eNodeB is coupled to the serving PDN gateway (SPGW) over the S1 interface.
As networks evolve to accommodate next generation capabilities, improvements in access nodes architecture as well an evolution in end to end architecture are desirable.